Designed to imitate the existing boulders found on the property, the Royd Clan’s House is made up of a set of pavilions that feature large open spaces and unique geometry. Nevertheless, this bespoke design lends itself to some structural challenges, including lateral stability, vertical load transfer, and connectivity.

To address some of these challenges, a XLAM CLT shear wall was incorporated into each pavilion. Running perpendicular to the GLT portal frames, the shear wall aids by transferring lateral forces from the exterior walls, floors, and roof to the ground foundation.

XLAM CLT was also used for the upper floors and roof diaphragm, as well as the inclined walls for each pavilion. These angled walls reduced the concrete slab surface, while simultaneously creating an improved connection with the upper mezzanine level.

XLAM prefabricated the XLAM CLT panels and XLAM GLT beams with CNC machines to ensure all elements could be assembled with a high degree of precision on site, which was crucial for a structure with such unique and complex geometry. In total, it took 10 days to erect the XLAM CLT panels and 15 days to erect the GLT beams.

In meeting the sustainability goal, over 220m³ of timber was used throughout the property, which converts to a total of 121kg of carbon sequestered from the atmosphere and stored within the timber. What’s more, the thermal performance of XLAM CLT also added great value to the property. Due to the thermal mass of XLAM CLT the temperature of the home remains stable throughout the day, keeping the home warm in winter and cool in summer, thus reducing energy usage and costs.

Sitting harmoniously within the bushland surrounds, The Seed House is a bold celebration of a mass timber used in a conventional build, featuring XLAM CLT and native timbers, natural stone, glass, and black steel. XLAM CLT panels and glulam beams were used to form the structure of the interconnected, cantilevered pods that make up the home.

Built predominately from XLAM CLT and glulam beams, mass timber forms the structural frames, cantilevered pods, as well as the spectacular spiral staircase, which elegantly winds down three floors. The XLAM CLTstructure has extravagant cantilevers exposed internally, with all exposed XLAM CLT elements containing hidden wall to floor connections.

In addition to the CLT Panels used througout the home, the feature spiral staircase is also prefabricated from XLAM CLT. To achieve necessary stiffness and stability, the treads were fitted individually and thread over a six-metre structural steel tube member. As individual treads were fitted, each one had to be screwed into place using hidden screw locations.

The strength of the house is largely reliant on the portal frames formed between the XLAM CLT floors and walls. The side walls wrapping the XLAM CLT cantilevered pods use both the longitudinal layer direction and the transverse layer direction, acting as deep beams to cantilever off steel portal frames. The kitchen is supported by a highly architecturally refined roof truss with a top chord of composite XLAM CLT and steel.

To overcome the challenging site, a pad foundation was laid to support steel posts, ties, and bearers. The long-span XLAM CLT floor panels were then simply coach-screwed in place through the upper USB bearer flange.

XLAM provided the XLAM CLT panels with extruded polystyrene sheet insulation factory-fixed to the underside. Timber plates were also pre-fixed to the panels along the bearing lines, to protect the polystyrene from crushing during delivery and assembly and to provide direct fixing between the XLAM CLT and steel bearers. This system proved highly effective and made for substantial labour savings on site.